formic acid in tetrahydrofuran T=0°C; 20 h; Title compound not separated from byproducts;

poly(4-vinylpyridinium tribromide) T=20°C; 2 h; neat (no solvent);

1: 64 percent / NaOAc, pyridinium chlorochromate / CH2Cl2 / 1 h / Ambient temperature 2: 1.) KOC(CH3)3 / 1.) THF, 0 deg C, 10 min, 2.) 0 deg C, 3.75 h 3: 88percent HCO2H / tetrahydrofuran / 20 h / 0 °C View Scheme

1: 1.) KOC(CH3)3 / 1.) THF, 0 deg C, 10 min, 2.) 0 deg C, 3.75 h 2: 88percent HCO2H / tetrahydrofuran / 20 h / 0 °C View Scheme

1: 49 percent / toluenesulfonic acid / benzene / 21 h / 40 - 50 °C 2: 64 percent / NaOAc, pyridinium chlorochromate / CH2Cl2 / 1 h / Ambient temperature 3: 1.) KOC(CH3)3 / 1.) THF, 0 deg C, 10 min, 2.) 0 deg C, 3.75 h 4: 88percent HCO2H / tetrahydrofuran / 20 h / 0 °C View Scheme